Power supply system and power supply control method

Abstract

The power supply system, which may be used with an electric car, extends the life of a high voltage battery while minimizing electric power required for vehicle actions. A temperature sensor measures a temperature of the high voltage battery. A controller preferentially drives first loads given first priority among a plurality of loads driven by the high voltage battery, other than a drive motor, based on an electric power amount that the high voltage battery is able to output and an electric power amount required by the drive motor for driving a vehicle when the temperature of the high voltage battery is not higher than a predetermined temperature. The controller preferentially drives in-vehicle devices of the highest priority among in-vehicle devices based on the electric power amount that the high voltage battery is able to output and the required electric power amount of the drive motor for driving the vehicle.

1 . A power supply system, comprising:
 a first battery for supplying electric power at a first voltage;   a second battery for supplying electric power at a second voltage lower than the first voltage;   a voltage converting unit connected to the first battery and the second battery,
 wherein the voltage converting unit is configured for receiving an electric current from the first battery, converting the first voltage into the second voltage, and then supplying the electric current to the second battery; 
   a measuring unit for measuring a temperature of the first battery;   one or more first loads driven by the second battery and given first priority;   one or more second loads driven by the second battery and given second priority; and   a control unit for preferentially driving the one or more first loads based on an electric power amount that the first battery is able to output and a required electric power amount of a drive motor for driving a vehicle,   wherein the control unit preferentially drives the one or more first loads when the temperature of the first battery is not higher than a predetermined temperature.   
     
     
         2 . The power supply system according to  claim 1 ,
 wherein the control unit further restricts supply of the electric power to part of a plurality of loads driven by the first battery, other than the driven motor, based only on the electric power amount that the first battery is able to output,   wherein the control unit restricts supply when the temperature of the first battery is higher than the predetermined temperature.   
     
     
         3 . The power supply system according to  claim 1 , wherein the control unit further suppresses output voltage of the voltage converting unit based on at least a state of charge of the second battery and a maximum voltage among drive voltages of a plurality of loads driven by the first battery, other than the drive motor. 
     
     
         4 . A power supply control method in a power supply system comprising:
 supplying electric power using a first battery at a first voltage;   supplying electric power using a second battery at a second voltage lower than the first voltage;   receiving an electric current at a voltage converting unit from the first battery, wherein the voltage converting unit is connected to the first battery and the second battery;   converting the first voltage into the second voltage using the voltage converting unit;   supplying the electric current to the second battery using the voltage converting unit;   measuring a temperature of the first battery using a measuring unit;   driving one or more first loads using the second battery and giving the one or more first loads first priority;   driving one or more second loads using the second battery and giving the one or more second loads second priority; and   controlling drive of the one or more first loads and the one or more second loads using a control unit; and   preferentially driving the one or more first loads, using the control unit, based on an electric power amount that the first battery is able to output and a required electric power amount of a drive motor for driving a vehicle,   wherein the control unit preferentially drives the one or more first loads when the temperature of the first battery is not higher than a predetermined temperature.